I had this conversation with someone already, but am I not correct in thinking that "mo chlann" can mean "my siblings" ?
I always learned in school that it means "family". Maybe it's a regional thing.
Ya, you see I lean't that it's not quite family, because it doesn't include your parents, aunts and uncles, cousins or grandparents for example. "teaghlach" is family, which includes all of those. But as you say, maybe it's different regional uses.
I learned chlann as a direct translation of family including parents, this was in connaught.
Clann means one's children, descendants or (rarely) followers. It does not include your parents.
In the narrowest sense, clann means a couple's children. This can indeed mean your siblings and you, taken together as a whole (ie all your parents' children). It can also sometimes mean family, as in "My wife and I have a large family - we have six kids."